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Magnetic field effects

Clevin Handschin, Peter Makk, Peter Rickhaus, Romain Maurand, Kenji Watanabe, Takashi Taniguchi, Klaus Richter, Ming-Hao Liu, Christian Schönenberger
At high magnetic fields the conductance of graphene is governed by the half-integer quantum Hall effect. By local electrostatic gating a pn-junction perpendicular to the graphene edges can be formed, along which quantum Hall channels co-propagate. It has been predicted that if only the lowest Landau level is filled on both sides of the junction, the conductance is determined by the valley (isospin) polarization at the edges and by the width of the flake. This effect remained hidden so far due to scattering between the channels copropagating along the pn-interface (equilibration)...
August 14, 2017: Nano Letters
Dongwoo Shin, Yongwoo Lee, M Sasaki, Yoon Hee Jeong, Franziska Weickert, Jon B Betts, Heon-Jung Kim, Ki-Seok Kim, Jeehoon Kim
Ohm's law is a fundamental paradigm in the electrical transport of metals. Any transport signatures violating Ohm's law would give an indisputable fingerprint for a novel metallic state. Here, we uncover the breakdown of Ohm's law owing to a topological structure of the chiral anomaly in the Weyl metal phase. We observe nonlinear I-V characteristics in Bi0.96Sb0.04 single crystals in the diffusive limit, which occurs only for a magnetic-field-aligned electric field (E∥B). The Boltzmann transport theory with the charge pumping effect reveals the topological-in-origin nonlinear conductivity, and it leads to a universal scaling function of the longitudinal magnetoconductivity, which completely describes our experimental results...
August 14, 2017: Nature Materials
Qian Zhang, Jieqiong Hu, Diyuan Zheng, Anhua Dong, Hui Wang
We report a large magnetically tuned lateral photovoltaic effect (LPE) observed in nanoscale Co-SiO2-Si structures. This tunable effect strongly depends on the location of two electrodes. The change ratio of lateral photovoltage (LPV) can reach up to a considerable value of 94.15% under external magnetic field of 1.77 Teslas. This phenomenon is mainly ascribed to the asymmetric Lorentz force acting on the photo-current in the region of edge area of the nanostructure. It adds a new functionality to the traditional LPE-based devices, and provides a potential prospect for the development of multifunctional high-sensitive photoelectric devices or sensors...
August 14, 2017: Nanotechnology
Irena Rektorová, Ľubomíra Anderková
Transcranial noninvasive brain stimulation includes both repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). TMS uses a rapidly changing magnetic field to induce currents and action potentials in underlying brain tissue, whereas tDCS involves the application of weak electrical currents to modulate neuronal membrane potential. In this chapter, we provide a literature review with a focus on the therapeutic potential of both techniques in the treatment of nonmotor symptoms of Parkinson's disease (PD)...
2017: International Review of Neurobiology
Ouri Cohen, Ming Zhao, Erez Nevo, Jerome L Ackerman
PURPOSE: To demonstrate a proof of concept of magnetic resonance (MR) coagulation, in which MR imaging scanner-induced radiofrequency (RF) heating at the end of an intracatheter long wire heats and coagulates a protein solution to effect a vascular repair by embolization. MATERIALS AND METHODS: MR coagulation was simulated by finite-element modeling of electromagnetic fields and specific absorption rate (SAR) in a phantom. A glass phantom consisting of a spherical cavity joined to the side of a tube was incorporated into a flow system to simulate an aneurysm and flowing blood with velocities of 0-1...
August 9, 2017: Journal of Vascular and Interventional Radiology: JVIR
Yu Iwasaki, Yoshiaki Hashimoto, Taketomo Nakamura, Shingo Katsumoto
The highly successful Dirac equation predicts peculiar phenomena such as Klein tunnelling and Zitterbewegung (ZB) of electrons. From its conception by Erwin Schrödinger, ZB has been considered key in understanding relativistic quantum mechanics. However, observing the ZB of electrons has proved difficult, and instead various emulations of the phenomenon have been proposed producing several successes. Concerning charge transport in semiconductors and graphene, expectations were high but little has been reported...
August 11, 2017: Scientific Reports
Alexander M Puckett, Saskia Bollmann, Markus Barth, Ross Cunnington
Attention to sensory information has been shown to modulate the neuronal processing of that information. For example, visuospatial attention acts by modulating responses at retinotopically appropriate regions of visual cortex (Puckett and DeYoe, 2015; Tootell et al. 1998). Much less, however, is known about the neuronal processing associated with attending to other modalities of sensory information. One reason for this is that visual cortex is relatively large, and therefore easier to access non-invasively in humans using tools such as functional magnetic resonance imaging (fMRI)...
August 8, 2017: NeuroImage
Saman Samadi, Mahboubeh Moradkhani, Hoda Beheshti, Mohammad Irani, Majid Aliabadi
In this work, the synthesized graphene oxide/TiO2/doxorubicin (GO/TiO2/DOX) composites were loaded into the chitosan/poly(lactic acid) (PLA) solutions to fabricate the electrospun chitosan/PLA/GO/TiO2/DOX nanofibrous scaffolds via electrospinning process. The synthesized composites and nanofibers were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Three-factor three-level central composite design was used to determine the influence of PLA to chitosan ratio, TiO2/DOX content and GO/TiO2/DOX content on the release of DOX from nanofibrous scaffolds...
August 8, 2017: International Journal of Biological Macromolecules
Bilal A Tahir, Chris M Bragg, Jim M Wild, James A Swinscoe, Sarah E Lawless, Kerry A Hart, Matthew Q Hatton, Rob H Ireland
To investigate the effect of beam angles and field number on functionally-guided intensity modulated radiotherapy (IMRT) normal lung avoidance treatment plans that incorporate hyperpolarised helium-3 magnetic resonance imaging ((3)He MRI) ventilation data. Eight non-small cell lung cancer patients had pre-treatment (3)He MRI that was registered to inspiration breath-hold radiotherapy planning computed tomography. IMRT plans that minimised the volume of total lung receiving  ⩾20 Gy (V20) were compared with plans that minimised (3)He MRI defined functional lung receiving  ⩾20 Gy (fV20)...
August 11, 2017: Physics in Medicine and Biology
Lin Sun, Sheng Zhang, Zhijie Jiang, Qi Yang, Sanping Chen, Yiquan Zhang, Wenyuan Wang, Qing Wei, Gang Xie
It is crucial to promote axiality to enhance easy-axis magnetic anisotropy. Two mononuclear Dy(III) compounds, in which each Dy(III) is nine-coordinated, namely, [(C12H10N5O)Dy(NO3)2(H2O)2]·C2H5OH (1) and [(C12H10N5O)Dy(NO3)2(C2H5OH)2]·H2O (2) (HL = N(3)-(2-pyridoyl)-4-pyridinecarboxamidrazone), have been prepared through controlling the amount of C2H5OH and H2O solvents. Geometry modulations were realized by interchanging coordinated and lattice solvents, thus achieving a structure closer to the configuration of a capped square antiprism for 2 compared to that for 1...
August 11, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Malika Denis, Timo Fleig
We present an updated electron electric dipole moment (EDM) effective electric field of Eeff= 75.2 GV/cm and (229)Th magnetic hyperfine interaction constant A|| = -1266 MHz, the nucleon-electron scalar-pseudoscalar interaction constant WS = 106.0 kHz, and the molecule-frame static electric dipole moment D = -4.41 D for the Δ13 science state of ThO. The criticisms of the results from Fleig and Nayak [J. Mol. Spectrosc. 300, 16 (2014)] made in Skripnikov and Titov [J. Chem. Phys. 142, 024301 (2015)] are addressed and largely found to be unsubstantiated within the framework of the present approach...
December 7, 2016: Journal of Chemical Physics
Joseph V Rispoli, Steven M Wright, Craig R Malloy, Mary P McDougall
BACKGROUND: Human voxel models incorporating detailed anatomical features are vital tools for the computational evaluation of electromagnetic (EM) fields within the body. Besides whole-body human voxel models, phantoms representing smaller heterogeneous anatomical features are often employed; for example, localized breast voxel models incorporating fatty and fibroglandular tissues have been developed for a variety of EM applications including mammography simulation and dosimetry, magnetic resonance imaging (MRI), and ultra-wideband microwave imaging...
2017: Journal of Biomedical Graphics and Computing
Renkun Huang, Ruowen Liang, Haimei Fan, Shaoming Ying, Ling Wu, Xuxu Wang, Guiyang Yan
With increasingly stringent environmental regulations, the removal of nitrogen-containing compounds (NCCs) from gasoline fuel has become a more and more important research subject. In this work, we have successfully synthesized TiO2/α-Fe2O3 heterogeneous photocatalysts with different mass ratios of TiO2 vs. α-Fe2O3. Taking photocatalytic denitrification of typical alkali NCCs, pyridine, in gasoline fuel under visible light irradiation (λ ≥ 420 nm) as the model reaction, the TiO2/α-Fe2O3 hybrids have exhibited enhanced photocatalytic activity compared with pure TiO2 and α-Fe2O3, giving a pyridine removal ratio of ∼100% after irradiation for 240 min...
August 10, 2017: Scientific Reports
Juan Manuel Marmolejo-Tejada, Kapildeb Dolui, Predrag Lazic, Po-Hao Chang, Soren Smidstrup, Daniele Stradi, Kurt Stokbro, Branislav K Nikolic
The control of recently observed spintronic effects in topological-insulator/ferromagnetic-metal (TI/FM) heterostructures is thwarted by the lack of understanding of band structure and spin textures around their interfaces. Here we combine density functional theory with Green's function techniques to obtain the spectral function at any plane passing through atoms of Bi2Se3 and Co or Cu layers comprising the interface. Instead of naively assumed Dirac cone gapped by the proximity exchange field spectral function, we find that the Rashba ferromagnetic model describes the spectral function on the surface of Bi2Se3 in contact with Co near the Fermi level EF(0), where circular and snowflake-like constant energy contours coexist around which spin locks to momentum...
August 10, 2017: Nano Letters
Liping Wang, Frédéric Labrosse, Reyer Zwiggelaar
PURPOSE: Automated and accurate tissue classification in 3D brain Magnetic Resonance images is essential in volumetric morphometry or as a preprocessing step for diagnosing brain diseases. However, noise, intensity inhomogeneity and partial volume effects limit the classification accuracy of existing methods. This paper provides a comparative study on the contributions of three commonly used image information priors for tissue classification in normal brains: image intensity, local and multi-atlas priors...
August 10, 2017: Medical Physics
Marcos Martinez-Banaclocha
The close anatomical and functional relationship between neuronal circuits and the astroglial network in the neocortex has been demonstrated at several organization levels supporting the idea that neuron-astroglial crosstalk can play a key role in information processing. In addition to chemical and electrical neurotransmission, other non-synaptic mechanisms called ephaptic interactions seem to be important to understand neuronal coupling and cognitive functions. Recent interest in this issue comes from the fact that extra-cranial electric and magnetic field stimulations have shown therapeutic actions in the clinical practice...
August 6, 2017: Neuroscience
Dainan Zhang, Miaoqing Wei, Tianlong Wen, Yulong Liao, Lichuan Jin, Jie Li, Qiye Wen
MnZn ferrite thin films were deposited on p-Si substrate and used as the dielectric layer in the graphene field effect transistor for infrared and terahertz device applications. The conditions for MnZn ferrite thin film deposition were optimized before device fabrication. The infrared properties and terahertz wave modulation were studied at different gate voltage. The resistive and magnetic MnZn ferrite thin films are highly transparent for THz wave, which make it possible to magnetically modulate the transmitted THz wave via the large magnetoresistance of graphene monolayer...
August 8, 2017: Nanoscale Research Letters
Kazuyuki Yusa, Hideyuki Yamanochi, Akira Takagi, Mitsuyoshi Iino
OBJECTIVES: Recently, three-dimensional printing models based on preoperative computed tomography and magnetic resonance imaging images have been widely used in medical fields. This study presents an effective use of the three-dimensional printing model in exploring complex spatial relationship between the tumour and surrounding tissue and in simulation surgery based planning of the operative procedure. MATERIAL AND METHODS: The patient was a 7-year-old boy with ameloblastic fibro-odontoma...
April 2017: Journal of Oral & Maxillofacial Research
Rajiv Chopra, Sumbul Shaikh, Yonatan Chatzinoff, Imalka Munaweera, Bingbing Cheng, Seth M Daly, Yin Xi, Chenchen Bing, Dennis Burns, David E Greenberg
Treatment of prosthetic joint infection (PJI) usually requires surgical replacement of the infected joint and weeks of antibiotic therapy, due to the formation of biofilm. We introduce a non-invasive method for thermal destruction of biofilm on metallic implants using high-frequency (>100 kHz) alternating magnetic fields (AMF). In vitro investigations demonstrate a >5-log reduction in bacterial counts after 5 minutes of AMF exposure. Confocal and scanning electron microscopy confirm removal of biofilm matrix components within 1 minute of AMF exposure, and combination studies of antibiotics and AMF demonstrate a 5-log increase in the sensitivity of Pseudomonas aeruginosa to ciprofloxacin...
August 8, 2017: Scientific Reports
Kun Li, Jun Du, Li-Xin Huang, Li Ni, Tao Liu, Hui-Lin Yang
We performed this meta-analysis to examine the diagnostic accuracy of MRI for the diagnosis of anterior cruciate ligament (ACL) injury in comparison to arthroscopy. We also compared the diagnostic accuracy of MRI with magnetic field intensities (MFI) greater than or equal to 1.5T with those below 1.5T, in addition to different MRI sequences. Studies relevant to the diagnosis of ACL injury by MRI and arthroscopy were analyzed. Computer and manual retrieval were carried out on studies published between January 1, 2006 and May 31, 2016...
August 8, 2017: Scientific Reports
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